import com.aliyun.odps.udf.UDF;

public class pro_serial_no extends UDF {
    // TODO define parameters and return type, e.g:  public String evaluate(String a, String b)
    public String evaluate(String s1,String s2) {
        String result;
        if(s2 != null || s2 !=""){
            result = s2;
        }else{
            result =s1;
        }

        return result;
    }
}